Multi-mode switching converters such as direct current-to-direct current (DC-DC) converters have different modes of operation for different load conditions. These different modes of operation are needed to provide a desirable mode of operation for a particular load condition. Typically, a desirable mode of operation is one in which a peak efficiency for energy transfer is achieved for a given load condition. One mode of operation is pulse width modulation (PWM), which is a form of pulse-time modulation wherein durations of pulses are varied while pulse frequency remains relatively constant. A multi-mode switching converter achieves a maximum efficiency for energy transfer from one supply voltage level to another while using PWM for loads having a relatively moderate current draw to a relatively heavy current draw. Another mode of operation is pulse frequency modulation (PFM), which is a form of pulse time modulation wherein a pulse repetition rate is varied, while pulse width remains relatively constant. A multi-mode switching converter achieves a maximum efficiency for energy transfer from one supply voltage level to another while using PFM for loads having a relatively light current draw to a relatively moderate current draw. At some point within a range of relatively moderate load currents a transition between the PWM mode and the PFM mode is necessary to maintain a desired efficiency for energy transfer. What is needed is a detector circuit to assist a controller for a multi-mode switching converter in determining if a transition from the PWM mode to the PFM mode or vice versa is required to maintain efficiency energy transfer from one supply voltage level to another.